Oxalic acid can effectively remove the rust, converting it into ferrous oxalate. A rinse with water afterward can restore the surface to a bright, new appearance. Additionally, the metal surface treated with oxalic acid becomes passivated, reducing its susceptibility to further rusting.

The difference between 201 and 304 stainless steel lies in their chemical compositions. The chemical formula for 201 is 1Cr17Mn6Ni5, while that for 304 is 06Cr19Ni10. The primary distinction lies in their nickel-chromium content. 304 contains 19% chromium and 10% nickel, whereas 201 contains 17% chromium and 5% nickel. Their corrosion resistance differs: 201, with higher manganese content, has a bright surface with a dark luster and is more prone to rust due to its higher manganese content. On the other hand, 304, with higher chromium content, exhibits a matte surface and is more resistant to rust. Stainless steel's resistance to rust is due to the formation of chromium-rich oxide on the steel surface. 201 belongs to the high-manganese stainless steels and has higher hardness and lower nickel content compared to 304.